The present invention is directed to stains suitable for application to porous substrates. More specifically, the invention relates to alkyd-based stains that can be cured by free radical curing.
There are a number of considerations relevant to coatings for wood substrates, such as cabinets, furniture, and the like. For example, the coating compositions should be curable without the need to apply excessive heat; wood substrates cannot be subjected to the high temperatures that can be used to cure coatings, for example, on metal substrates. In addition, it is desirable that the coatings offer sufficient resistance to mar and scratch, while at the same time having an aesthetically pleasing appearance. Finally, as with most coatings, environmental considerations are also relevant. Thus, improved coatings taking into account all of these considerations are desired.
The present invention is directed to coating compositions, specifically stains, comprising a polymer, an initiator, and one or more pigments and/or dyes as the colorant. The polymer comprises an alkyd portion or moiety and a free radical curable portion or moiety. An alkyd, as is known in the art, is the reaction product of a polybasic acid and a polyhydric alcohol in the presence of an oil or fatty acid. Thus, the alkyd portion of the polymer can comprise a fatty acid moiety. An appropriate free radical initiator is selected based upon the type of free radical moiety used.
It will be understood that the present compositions can be cured by free radical cure. When the fatty acid moiety of the alkyd is derived primarily from a drying or semi-drying oil, the present compositions are also capable of oxidative cure, that is, cure at ambient temperature upon exposure to air. Significantly, the dual curing mechanism of certain embodiments of the present compositions does not interfere with the properties obtained from the cured coatings; indeed, the dual curing mechanism of certain embodiments may improve the properties obtained from the cured coatings.